1. Field of the Invention
The present invention relates to a lift-off cover assembly for ships, barges or the like which includes a plurality of adjacently positioned curved sections and end sections. The cover assembly can be made of a semirigid to rigid lightweight material such as fiberglass reinforced resin and is adapted to be placed on the barge so as to define a protected storage space thereunder.
2. Discussion of the Background
A barge cover assembly has been described in my earlier application entitled xe2x80x9cA Lift-Off Cover Assembly For a Barge,xe2x80x9d U.S. application Ser. No. 09/373,577, U.S. Pat. No. 6,138,597 (the xe2x80x9cprevious cover assemblyxe2x80x9d), the contents of which are hereby incorporated by reference herein. The previous cover assembly is superior to known barge cover assemblies in many respects. I have since conceived of several improvements to the previous cover assembly.
One issue noted with the previous cover assembly is that mishandling may lead to cracks being developed at or near the locations where side stairways protrude from the profile of the ribs. It would be desirable to eliminate these potential cracks even when cover sections are mishandled.
The previous cover assembly provides advantageous doors which receive a significant amount of wear and tear, some of which occurs during stacking and unstacking of the cover sections. The reduction of wear and tear on the doors, especially that which occurs during stacking and unstacking of cover sections, is desirable.
Another feature of the prior generation assembly is the provision of raised edges on the sides of stairs on end cover sections. These were provided to clearly define step areas, and/or raised steps. The incorporation of this feature absorbs additional man hours and material in the manufacturing process as the placement of xe2x80x98wetted outxe2x80x99 woven roving sections, also referred to as passes, in these areas may require cutting of the woven rovings to make them fit properly. What is needed is an end cover stair section that can be clearly identified and fabricated without requiring manufacturing personnel to cut wetted out roving sections in the manufacturing process.
Accordingly, an object of this invention is to provide for a lift-off cover assembly for barges which addresses the above-mentioned issues and includes the following features.
In one aspect of the present invention, side stairs (stairways that are oriented in the port/starboard direction rather than the bow/stern direction) are provided such that steps and risers are completely within the rib profiles. That is, the stairs are formed such that no portion of a riser or step protrudes above the top/peak of a rib or below the bottom/valley of a rib. Because the stairways are provided within the rib profiles, the stairways are protected during stacking and unstacking handling operations.
Another aspect of the present invention is the provision of low profile doors (which protect and keep dry grain and/or other products on the barge) that extend only slightly beyond the tops/peaks of ribs such that the doors are not impacted when cover sections are stacked. This reduces the wear and tear on the doors. Additionally, the size of the doors are altered with respect to the previous cover assemblies. The door opening is sized and shaped to accept a standard 4 ft.xc3x978 ft. sheet of material. This feature allows a repair to be easily affected in the event that a door is missing by simply obtaining a 4xc3x978 sheet of a material such as plywood and taping the plywood into the opening. This ease of repair is important in locations such as docks where access to tools to cut material such as plywood to fit non-standard size openings is not always available.
The present invention also provides end cover sections with center stairways (stairways that are oriented in the bow/stern direction and that are aligned with a center pathway) that can be fabricated without the necessity of cutting woven roving sections. Impregnator machines are often used during the manufacturing process. Machines such as these can produce continuous sheets of multiple layers (e.g. three 24 oz woven roving layers) at once. The continuous sheet have a width of, for example, twenty seven inches. These sheets of material are layed up across the width of the molds one sheet at a time side by side (typically with a three inch overlap) to form cover sections. The raised edges and raised steps provided with the center stairways of the previous cover sections presented manufacturing process issues addressed in part by requiring these layers to be cut at the location of the raised edge. By providing center stairways with a noticeable but smooth curve at the edges of the width of the steps, rather using a raised section to define the width of the stairway, and by using the peaks and valleys of successive ribs for the steps, the stairways can be manufactured without requiring cutting of the layer sections while still providing for an easily recognizable and well defined stairway.